Potato virus X (PVX) is a plant pathogenic virus of the family ''
Alphaflexiviridae'' and the order ''
Tymovirales
''Tymovirales'' is an order of viruses with five families. The group consists of viruses which have positive-sense, single-stranded RNA genomes. Their genetic material is protected by a special coat protein.
Description
Tymoviruses are mainly ...
''.
PVX is found mainly in
potatoes and is only transmitted mechanically. There are no insect or fungal vectors for this virus. This virus causes mild or no symptoms in most potato varieties, but when
Potato virus Y is present, synergy between these two viruses causes severe symptoms in potatoes. The virion has helical symmetry and a deeply grooved, highly hydrated surface and is made of a single-stranded positive-sense RNA genome of approximately 6.4 kb. This is wrapped in approximately 1300 units of a single coat protein (CP) type, with 8.9 CP units per helix turn. The genome is capped at the 5′-end and poly-adenylated at the 3′-terminus. It contains five open reading frames (ORFs) encoding five proteins: the RNA-dependent RNA Polymerase (RdRP), the movement proteins encoded by three overlapping ORFs that form the Triple Gene Block module (TGBp1, TGBp2, and TGBp3), and the CP (coat protein).
Virus indexing and limited generation production of potato, which starts from disease-free tissue culture plantlets, has nearly eliminated this virus from many countries' potato supply.
Hosts
''
Solanum tuberosum'', ''
Lycopersicon esculentum'' and ''
Nicotiana tabacum''.
Use in research
Chapman et al. 1992 introduced the use of
transgenic
A transgene is a gene that has been transferred naturally, or by any of a number of genetic engineering techniques, from one organism to another. The introduction of a transgene, in a process known as transgenesis, has the potential to change the ...
PVX as a
plant transformation vector
Plant transformation vectors are plasmids that have been specifically designed to facilitate the generation of transgenic plants. The most commonly used plant transformation vectors are termed binary vectors because of their ability to replicat ...
.
It has since been used by Kumagai et al. 1995 in the discovery of what is now known as
virus-induced gene silencing
RNA interference (RNAi) is a biological process in which RNA molecules are involved in sequence-specific suppression of gene expression by double-stranded RNA, through translational or transcriptional repression. Historically, RNAi was known by o ...
, by Thomas et al. 2001 to improve Kumagai's process, by De Kock et al. 2004 to investigate ''
Nicotiana
''Nicotiana'' () is a genus of herbaceous plants and shrubs in the Family (biology), family Solanaceae, that is Native plant, indigenous to the Americas, Australia, Southwestern Africa and the South Pacific. Various ''Nicotiana'' species, common ...
''s
Cf proteins and
Cf genes and their production of
host resistance
Plant disease resistance protects plants from pathogens in two ways: by pre-formed structures and chemicals, and by infection-induced responses of the immune system. Relative to a susceptible plant, disease resistance is the reduction of pathoge ...
responsive to pathogen
extracellular protein 2
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions ...
(ECP2) (and by others to investigate various other
hostpathogen interactions in ''S. tuberosum'', ''L. esculentum'' and ''N. tabacum'')
and by Tameling et al. 2007 to investigate plant
nucleotide binding leucine-rich repeat
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules with ...
s (NB-LRRs).
See also
*
Viral diseases of potato
References
External links
ICTVdB—The Universal Virus Database: Potato virus X—The Two-Faced Potato Virus X: From Plant Pathogen to Smart Nanoparticle
Potexviruses
Viral plant pathogens and diseases
{{Virus-plant-disease-stub